1. Field
The disclosure relates to a method, system, and article of manufacture for the representation of system clock changes in time based file systems.
2. Background
Information technology systems, including storage systems, may need protection from site disasters or outages. Furthermore, information technology systems may require features for data migration, data backup, or data duplication. Implementations for disaster or outage recovery, data migration, data backup, and data duplication may include mirroring or copying of data from one storage system to another. For example, in certain information technology systems, data may be replicated from a primary storage system to a secondary storage system. If the primary storage system is unavailable, then the replicated data in the secondary storage system may be used instead of the unavailable data in the primary storage system.
Recovery point objective is the point in time to which data must be restored in order to resume processing after a loss of data. For example, if a trade execution program of a stock exchange fails then certain data may be lost if all data is not synchronously backed up to the secondary storage. The recovery point objective is the point in time to which the trade execution program and any lost data should be restored. To achieve recovery point objectives and also for other reasons, a time based file system may be used. A time based file system is a file system in which the image, i.e., copy, of the file system at any point in time is preserved. The preserved image may be used to revert back the file system to an earlier point in time, wherein the file system may be reverted to the earlier point in time for a variety of reasons, including the occurrence of site disasters or outages.